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Q 7 I 2 Sheets-Sheet 1.

D PgFITZGER-ALD a; W. LYON.- AUTOMATIG TENSION FOR SEWING MACHINES.

No. 291.706. Patented Jam. 8, 1884.

(No Model.)

I I A WW a v WITNESSES: INVENTORI),

(No'Mode-l.) 2 Sheets-Sheet 2.

D. P. FITZGERALD &'W. LYON.

AUTOMATIC TENSION FOR SEWING'MAGHINES. N0. 291,706. Ilh tented Jan. 8,884.

WITNESSES Z N PETERS. llwlwlllhngmpllcr. wqahin tttt C UNTTnn TATESPATENT @rrrcs.

DANIEL P. FITZGERALD AND \VlLLIAM LYON, OF NEVVABK, NEW JERSEY.

AUTOMATIC TENSION FOR SEVVING=MACHINES.

SPECIFICATION forming part of Letters Patent No. 291,7C6, dated January8, 1884.

Application filed August 4, 1883.

(No model.)

To aZZ whom it may concern.-

Be it known that we, DANIEL P. FITZGER- ALD and WILLIAM LYON, bothcitizens of the United States, and both residents of Newark,

in the county of Essex and State of New Jen.

sey, have invented certain new and useful Improvements in AutomaticTensions for Sewing-Machines; and we do hereby declare that thefollowing is a full, clear, and exact de scription of the invention,which will enable others skilled in the art to which it appertains tomake and use the same, reference being had to the accompanying drawings,which form a part of this specification.

Our invention has relation to that class of automatic tension devicesfor sewing-machines in which the thread is constantly subjected to agentle pressure by a spring, and to a stronger pressure, which isintermittently relieved by the operating parts of the machine after theloop has been drawn, to complete or nearly complete the stitch, ashereinafter more fully described and claimed.

This device is adapted, by slight modifications in its construction, tobe operated either by the needle-bar or by the connecting-rod of themachine, as may be desired, and according to the style or pattern onwhich the device is to used, as will be seen by reference to theaccompanying two sheets of drawings, in which Figure l is a sideelevation of part of a sewing-machine provided with our automatictension as adapted to be operated by the me dle-bar. Fig. 2 is a sideelevation of part of the same machine provided with our automatictension as adapted to be operated by the connecting-rod. Fig. 3 is aperspective view of the tension device shown in Fig. 1. Fig. 4 is asimilar view of the tension device shown in Fig. 2. Fig. 5 is alongitudinal sectional view of the spring-inclosing box H in Fig. 3.Fig. 6 is similar view of the spring-inclosing box marked H in Fig. 4,and Fig. 7 is a rear elevation of part of a sewing-machine with ourtension device as adapted to be operated by the connecting-rod of themachine.

Like letters of reference indicate corresponding parts in all thefigures.

Our improved automatic thread-clamping and tension mechanism issupported by and the frame or plate B are the stud G and cy- I lindricalarm D, parallel to each other. Stud C forms the pivot or fulcrum for anarm or lever, E, which is balanced up on its fulcrumthat is to say, armE is a lever of the first class, with its fulcrum C at or near itscenter of gravity. here one arm of the lever is longer than the other,as in Figs. 1 and 3, the short arm is made so much heavier as to balancethe longer arm.

In that form or modification of our automatic tension which isillustrated by Figs. 1, 3, and 5that is to say, where the device isadapted to be actuated by the needle-bar of the machine-the short arm oflever E is provided with a set-screw, F, having a checknut, f, forholding it firmly in -its adj usted position, so that it shall not workloose by the jarring of the machine. The lower end of this screw bearsagainst a cap, g, upon a spring, G, inclosed within abox, H, which is bypreference cast upon or in one piece with the supporting-frame B. Thelong arm of lever E bears against the cylindrical arm D, and it followsthat the pressure of the lever against the arm may be regulated byadjusting the set-screw F. v

I is a' strong spring, one end of which is suitably fastened upon frameB, while its'free end is bent to form a plate or shoe, 1, which overlapsand bears against the outer end of lever E. Shoe I should have a leatherlining or covering, i, on its under side, to prevent noise as it isstruck by reciprocating needlebar, J, on each of its upstrokes.

The operation of this form of the device is as follows: The thread shownat T is taken from a spool, placed upon a suitably-arrangedspool-spindle, and is carried through an aperture, e, in the long arm oflever E, and between the under side of the lever and arm D. The coarserthe thread the greater, of course, will be the pressure exerted upon it,as against arm D, by the lever-arm and the spring G. This pressure iswhat we have termed the moderate pressure, which obtains during theintervals of forming the stitch by drawing the loop up to the goods; butthere is another strong pressure exerted upon lever E by the spring I.This pressure is, however, intermittent,inasmuch as it is broken everytime the free end of the spring is lifted off of the lever by theneedle-bar J striking against it on the upstroke, and this occurs afterthe loop has been drawn to complete the stitch, or nearly so.

For the purpose of regulating or fixing the throw of the free end ofspring I, we provide the upper end of the needle-bar with an adjustablenut, J, which may be fixed in its position after adjustment by acheck-nut, j. Thethicker or coarser the threadbetween arm D and lever Ethe greater, of course, will be the pitch or elevation of the outer endof the lever, and as that end of the lever carries the shoe 1 of springI with it, it will be seen that it admits of a longer stroke of theneedle-bar before contact ensues, and that the time during whichpressure by spring I is exerted upon the thread is proportionatelyincreased. In other words, the coarser the thread the shorter theintermittent periodsof contact between the top of the needle-bar and theunder side of shoe 1. As the thread leaves arm D, it is carried througha thread-guide, E, fixed upon arm E, to the pull-off, and thence to theneedle in the usual manner.

In the modified form of our device, as represented in Figs. 2, 4, 6, and7 of the drawings, which is for the purpose of adapting the tension tobe actuated by the connecting-rod K, lever E is bent at right angles,and spring G bears with its cap 9 against the bent arm of thelever,wh'ich presses against arm D. The tension of spring G is adjustedin this case by a screw, F, inserted through the end of box H, and whichoperates in precisely the same manner and for the same purpose (via, forthe purpose of regulating the continuous moderate pressure onthe thread)as the set-screw F. In this construction we dispense with thethread-aperture 0, but carry the thread '1 from the spool through thecurved thread-guide E, then between arm D and the lever, and then againback through the thread-guide to the pull-ofl1 The shoe 1 of spring I isstruck intermittently by a projecting bracket or tappet, K, upon theconnecting-rod K,which has an adjustable nut and check-nut at its upperend, operating in like manner and for precisel the same )urpose as nut Jand checknut j at the upper end of the needle-bar.

If desired, that part of the tension-lever E which bears against arm Dmay be widened for the purpose of preventing the thread from slippingfrom under it; and it is also obvious that the thread may be wound oneor more times around arm D, between it and the lever, when it isdesirable to have a taut or strong tension, as in gathering the goods orfor other purposes.

The spring I should be sufficiently stiff or strong to exercisesufficient pressure upon the thread to do the very strongest kinds ofsewing.

Having thus described our invention, we claim and desire to secure byLetters Patent of the United States- 1. In an automatic tension devicefor sewing-machines, a thread-clamping device composed of a stationarythread-rest or threadbearing, a lever bearing with one of its armsagainst the thread-rest, a spring adapted to operate continuously with agentle or moderate pressure against the lever, a spring adapted tooperate with a strong pressure against the lever, and means forintermittently raising said spring, releasing its pressure, constructedand combined substantially as and for the purpose shown and set forth.

2. In an automatic tension device for sewing-machines, a thread-clampingdevice composed of a stationary thread-rest or threadbearing, a leverbearing with one of its arms against the thread-rest, a spring adaptedto operate continuously against the lever, means or mechanism forregulating the tension of said spring, aspring adapted to operate with astrong pressure against the lever, and means for intermittently raisingsaid spring, releasing its pressure, constructed and combinedsubstantially as and for the purpose shown and set forth.

3. The combination of a supporting-frame secured upon the machineframe,a threadbearing lug projecting from said supportingframe, a lever of thefirst class, pivoted upon the supporting-frame and resting against thethread-bearing lug, a set-screw turning vertically in one end of thelever, a capped spring bearing against the lower end of said screw, aspring secured at one end to the supporting-frame and bearing withitsother end against the other end of the lever, and means from themechanism of the machine for intermittently raising said spring afterthe loop has been drawn up, as and for the purpose shown and set forth.

4. In an automatic tension device for sewing-machines, the combinationof a stationary thread rest or bearing, a lever bearing with one armagainst the thread-rest,a spring bearing continually with a gentlepressure against the lever, means for adjusting said pressure, a springbearing against the lever with a strong pressure, means from themechanism of the machine for intermittently raising said spring afterthe loop has been drawn up, and means for adjusting the throw of saidmechanism, as and for the purpose shown and set forth.

In testimony that we claim the foregoing as our own we have hereuntoafiixed our signatures in presence of two witnesses.

DANIEL I. FITZGERALD. WILLIAM LYON. WVitnesses:

HENRY C. KLEMM, ABRAHAM MANNnns.

